Distinct Bacterial Community Composition in Rice Paddy Soil of Ebonyi State, Nigeria: Elucidation of Community Structure and Soil Physicochemical Properties

Abstract

This study investigated the bacterial communities associated with different cultivars of rice from different flooded soil in Ebonyi State,  Nigeria using molecular techniques as well as the physicochemical and pore water ion concentrations of different rice fields.  Physicochemical parameters of sampled sites were determined using standard methods, while the pore water was analyzed using high  performance Liquid chromatography and Ion chromatography. The PCR amplification was done using three RAPD primers namely,  OPB05, OPT05 and OPB03 and resolved on agarose gel independently. The physicochemical parameters revealed the presence of sand,  silt, clay, sandy - loam and clay – loam which were predominant in the area investigated, pH was slightly acidic, while there were presence  of inorganic and inorganic elements.The amplified gel result of the three RAPD primers revealed that 9, 5, 7 polymorphic alleles  nd 22, 12, 31 distinctly visible bands across the bacterial isolates respectively with molecular base pairs ranging from  400bp-1300bp. Molecular identities of the bacterial isolates showed that Aeromonas hydrophila strain A210 16S, Pseudomonas  plecoglossicida strain RJ39 16S, Aeromonas caviae 16S, Escherichia coli strain 26561, Pseudomonas otitidis strain JK79 16S, Enterobacter  cloacae strain ES-2 16S, Serratia marcescens NBB1 16S and Aeromonas diversa strain 2478-85 16S were associated with the roots of  different Oryza spp. Phylogenetic relatedness among the isolates revealed that isolates B1, B3 and B10 are closely related. It showed that  90% of the isolates mainly belong to the gamma proteobacteria, while 10% belong to the firmicutes. The study has given insight and  understanding of the bacterial community composition of rice paddy soil in Ebonyi State.